This image released by the Colorado Avalanche Information Center, annotated with red lines, shows the site of two avalanches at Upper Senator Beck Basin, northwest of Red Mountain Pass in the San Juan Mountains. A group of skiers triggered the avalanche on the right and the avalanche on the left released sympathetically, adding to the debris pile of the first slide. A skier who died Saturday after being buried in the debris from both avalanches was participating in an advanced avalanche safety course at the time he was killed.